No, the game designer gets to enforce the rules. The majority can abide by the rules or they can leave. Voting with your wallet is the most powerful way of voting, after all.

If the rules in PvP area specify PvP battles and someone wants to battle that way, that's what they're allowed to do. If he did something illegal, it's up to the game designers to correct that. If he did something unethical, like teleporting a villain to a kill zone, he may be disliked.

At no point, though, should he be threatened with bodily harm or being bullied by the "majority". If they had ignored him and/or engaged him in battle, he'd have no data for his study.